Some mobile phones may comprise a display surface and a rear touch sensor. A user may use an application program (hereinafter, referred to as “application”) by inputting to the rear touch sensor. Also, some mobile phones may comprise two display surfaces. In such mobile phones, applications may be used in various conditions such as a condition in which a screen based on the application is displayed on one display surface, a condition in which the screen is displayed on two display surfaces, and the like.